SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57b9cd294d4cac2f9685138b9d0c789cd44982f0a24018e6cfe7897ef7f80514' 
  AND token = 'E62dAgsUPU8maLIjhWwYWk+X7rnhzTxkZxgF5NrH2cE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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