SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7af9dbf7d2076b74bcfca96c258eb40fa7a5b6bcfe45cd6fdb2613d45df673d' 
  AND token = 'e3S5DEtOP4/hvxxLEij206dpjfEHjMfxk5JoHYr56j4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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