SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e770b8775093925d27b1c94d8cad0e0cb79e514bbbe262bfd7f43de2fa48d737' 
  AND token = 'vNrTktP5fYgkVhnGo3vBr7dut9FyX16abLHajvWmukc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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