SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfe48439361a56eafca15c74b97b02d675daf21f664d349edc82d099c68af7fe' 
  AND token = 'KTLFJMnMuWmUWLDshjE4EXeZzhFfvO1qz8QVVb1VZdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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