SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a4df440c80ebc67b9921bd5ed3d84ee0e2c1a345057255dc91f57dac2178525' 
  AND token = 'l7QComjF7hB94jKnJQBXjjvmsdx5ADqLfVBhOUBwnJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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