SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a77e4c70625763abdf4afd0e7dd699d77dacde3c0baa08c62cc51413db15078' 
  AND token = 'VlWk4NIF/49TZPNhoS92kdb+2sLvRuA36pw3W9nhVqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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