SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5616963d3f76a39545a8c0de5bbe763ba8d8717f6bdd9def2c152baa912bf15' 
  AND token = 'jmeZOVXkGMv+S+cLpTb5HrRSh7EcNyMrGKqcNy1AK50=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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