SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e758ebd21021423f452320be17bb79906ba03ffaaf5cece228397d24079b8f01' 
  AND token = 'pgQIzCNyhtzCRy+k1fnN7JSSg8alghgCOdRfcRKqDSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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