SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f21d8db28a2662ec705898e2054754d42ced8b2bf068a2f2f0fd32a8fc65be9b' 
  AND token = 'ErqbO9CC/uyu4vaoTw/dfUQ1OyUCozcLbAK1kezUnB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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