SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5ae6e2d15b54f7f4e99e0dc66fa472e016db369da3309afe8c22676baab91a8' 
  AND token = 'PHLpw9QbHgCAHqv02CPgEBZO+Q+4urrLdqH4QbiwjZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}