SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '903fee176dc3e046224e59cef453945e98658d6c3d37083156103418942f5ac4' 
  AND token = 'GtBW+r5hpoVShpUK7KIe1NIv+KW8EI9rzgpm8TgtVIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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