SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f47bb8e43981f0d8358bac29ba7c3b0b0ee0786ff4d59bd9e5ec8511925d986' 
  AND token = 'NzzWKT5edijerpXsBTyF05mYJ9MhoktYE5E9/dsAabw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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