SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3e381dc9bbc3ad9f19056fa4a2fe0eb6ebdfb7cca6116a01fcf6534733dd92f' 
  AND token = 'MJOETpBRVp2RW0VLFzaywXbjt3uLrqs5KE4+l1CANn4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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