SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ccd5be6af78495b56450f13351030be98425ac6638adc0e1f45781c22f345c2' 
  AND token = 'COrGYb5tnnUJWpjAZEMn4RFDwJYch89o1uNmbE1eLrE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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