SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5137815a1eb7a8fc41273752f4cd9e1588ee8dcbb2025c46adea7ff929abb784' 
  AND token = 'JBRTRy+8uE0F+YiMwQVfs7bLeRRqd9hZK+gFgFGAGO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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