SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b352f437ade640fed4fcd8d8eea76c31ef625ac0fd800f82ae9375da5f8b7f2' 
  AND token = 'eGQak9nw0DHHIVgcCsvlYPhGr6NHsLiqhzf7lsf2gyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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