SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3f1627ebeb2b6c5aedfffadb02b112139cb4501f560a8bade1c6f576189fbd58' 
  AND token = 'o2xQUMfiBPMMwf+eY47egCf0nBoURE8blHgml91KEPg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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