SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bbde281003ddb1b5fc155a02ce15f720e363bed2c90a6ce36b12346a550412e' 
  AND token = 'TaBm7yFx9kzRdya9QuR7NVLPKWdPsDeMlETZgagaSKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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