SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6af17c7f69e6d157f2a3f47202bb29304aba40eb45d5651ef70667e4e6b99a49' 
  AND token = '1neEwDEnTm5v9YpV3v3GKOBudCOPB6Afl3fzTu0GWgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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