SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc2df43e5d216ed94ad3dfea316b40959eb9d56baa462f07782166406408e981' 
  AND token = 'fOt5Bs2+igK7+Jo1pqEMa+irR/27uIyYwI7/cHJaygc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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