SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e909689eb76bd4bcb9491c53b25a8e4216327672dcb032768487ab413f3a17bf' 
  AND token = 'cUTSMH961BeSyLCQ11rvpZIa1XqaCexpDU/7bZjXRuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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