SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63267999b59700425e849e152998f3f69e2511f330596029cbcb08b8f1bae290' 
  AND token = 'qUmNPdGtQiFUm0dRn8qvXNNarAOJfaTHCCNdJgGNcNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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