SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f6d50bf18c6267ad837fd886fdef00c2a6e019e93b796c98ca47bd2c254e659' 
  AND token = 'K1GjWz/FPbyfh+QF4JY2ySIq9Mvh7UPmSecMmLDD3as=' 
  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"
    }
  }
}