SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a76353bf72003870536d99bf7ca2da9094edf65188df451f9cfcd0300f1ec089' 
  AND token = 'XSyWczYZg+udg7VHqZGBFqhpY5+mX3UsgX0uoqlQAfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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