SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '056cc46a5fa398f5cd2e9249439a7fd621575d5eb01ce3e145744a2646cab2a0' 
  AND token = 'fbDxNtxjcGnY3cXMVE7BdTACKnoLuSmibAw1nQedZFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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