SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fb748f07fbe52931883d21cd9e757ec11b657cef3923ad34c3763cb20d44f74' 
  AND token = 'rMUoXfCpHxMf5plcC2kW3YGEuJfkdDoRqG5u6MWB7V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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