SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7077603604fb0d6a0399d934629c4cce3467fb92a3b21fa807c996ef47d0bdd' 
  AND token = 'lrY0sKSGNWF3gAFIe1/ncVwQ8CLQbg//LhH1gMg3uCc=' 
  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"
    }
  }
}