SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9710a1efaa0d1f400a4942bd8d286d3f1b8605d817e78c095c77aa73c2422102' 
  AND token = '+zxQH5zbzm0V/MP8H5Tud4HhDAnlUCu3M5XIEyxFGkQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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