SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cab0147453206776733ee341b50216f4d07e2dd69f669c5e8db3e864fc8a48f2' 
  AND token = 'hlYpZkL045I3e9hSyLzlsJkQYRQWyl2owMDP/PyIYJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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