SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb260fb5c03ead2fdd540eb1fb68e0d201fdc4bb55c486cfa42113fb4bc84cea' 
  AND token = '9cLwEW3XrDfaYbd4oeBAgMKtSRCy0QHDsklFaERInFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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