SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ec97aec50b552c164115587c9f1dbf80dfa9b78308f09d907eb7e1caadd7cc2' 
  AND token = 'S3rAmOVRKWFo/YV8+xf7Ge35/VCNWfDH5KghTholFQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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