SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a744317ee94cc4529ec23b2c1e71d7cc6354bc9a2253c5f52ad26388d5399649' 
  AND token = 'EWgnuvMJuimsb5jhzIsZ7UKBbgqUG0UjIAwy7QiHxrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}