SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '038a9670f4e813e223db344081078b702fc2496b968f918220c2dc324b8bdab2' 
  AND token = 'dKwOoCBYnuvEmRu7phuFqlQe4lHDJRBiWgm+ULxa/e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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