SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7abe6e675d0052a8c8fbb0faecf5179dcfe86985c94700384027486f36122aec' 
  AND token = 'm4TarnQeGSR8E7QqzKSqGZChvfFjrKNFEOn7oghwncg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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