SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6adea559980c54882111386ec6e554149cae9e1532bd87442ef8fe14b95b3f22' 
  AND token = 'ffrmTQqCa1zG/C9++zbbiNoUnEmEMleEh1+jVttjmeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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