SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76e1751847f7fbc1d8d715636a17e7e6b9d2afc76023774b95a1af2b1c645c0f' 
  AND token = '9ndXZ3fJKKh4ug6MalF2lrm2/IcOCn/6rAFLV8bzLqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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