SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c25b804d29be42927bc5f21314ffc28ede0ab516f48a8588755559e388ee9b28' 
  AND token = 'pGZjJwB1gQYJO5vGKOxnSloMMz/mutQFDG4Dpp4yuS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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