SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7ff71b4d90292e5f602571177e450efe3f4ffc228b6eca6cc53956616eedf06' 
  AND token = 'l++LBWVAELlbJV0AZoLebdUbn1HkW9F3eBSqSBHvfxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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