SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9933533bc028892e0bec4acea7d69de370c6d08ccf9942f00339f6a13488655' 
  AND token = 'kZkZeOTTzrSYzOCnmb1BbnNO01RmEKmapSYJgvbOWLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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