SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55663bc31d9147c0bd61766f49ce3fa0623e8c436a5659ca2554c22eff51bf07' 
  AND token = 'ximSNyMKxCTGtpvhBGs5KbEKtYbKWX7kOsKcGc2rgV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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