SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6b6483830b9ece734f7b8c56420423eb9626d2eb33781e66268d484209f163b' 
  AND token = 'iPkUujw2qrKfmzJf1vlZCJggaJ7RMvOlKwKwcPD13EY=' 
  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"
    }
  }
}