SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45a60559f9845058005cd795754032a831e75118d65b1bd0bddd197b239eac5b' 
  AND token = 'Lp8oDd+/fArby7snJNwTWRrYpXKl+wpRxNxG7tKPHRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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