SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67bd4bfbbaf9c15f3d12ced20979acf37f07076642fbc02af412f1da74d3016' 
  AND token = 'W9XjL35JNu69xOAVVfvb3AV8qcM1inriKBXgzlCIBCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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