SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a77d24bffc72073e1aeeab991f6660e51f03e4d24284606810c00d2612fabb84' 
  AND token = 'wnDUHPa6EYM8nPH47pEKsTY2V0WZYk2NK+BwZNQ/gCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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