SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '512462c40f3f718274dab8575b03b9c1191f59517dfa3acef8017da8afe072d1' 
  AND token = '0hkC/fvcQYlNwr4Vu2zuteKw34CJb9pnOsu0B03qwPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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