SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '868820ec08c41827d9d00d71335c2a4509a34d165e915c550379eb9eb59c5a79' 
  AND token = 'UGK+mxO+rOtlwQv3qOVavAQN9lj+/qzAQM8AuHMrgsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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