SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ea4057dcb2a9fb23e572cb0139992c61e6e69564343b067f10256fd7f881e8' 
  AND token = 'O82OWaHK0sdiVZwGheODDPiWMGXjoZhAsH6Auz6xLT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}