SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b2ee18d3e6f892d64723fb311533bc925e777c21a06837dff453b425d2a1c48' 
  AND token = '9qQTutWALEkMuWonIk9pM3XfSMM5y2V9S/o+MZH+ygY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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