SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccadec6f5830170eeff10483290e6638eeb7a5c4b66c8a66140613325b6062e1' 
  AND token = 'XeLElgeS8ddi29hS0vxL0tlArhwLnyrzGD5dcNPqsfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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