SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a48b869cdd8fcf219274defcb0dcf946044ea66eaba480543c48ad442c89fa0d' 
  AND token = 'Jat/R2kXkREQv26VIK38tkm8h55rAUwdAeC696tdn5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}