SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be7bf65d443459db00e4490ffdb88412e4292808045ebd57d62e81a96f3abe79' 
  AND token = 'hEKr4oxin2MQFNRorPPPOV2/+Ah4kp3zPWGvBjcw6f8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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