SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52b53b18d57b19e40d81a94471f16551dff3adac53b065a56cf44546a9f974a7' 
  AND token = 'fOCPRXbp9K9YtrLj27ena/9DFgOyY+0C2P1DexEmqLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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