SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '981cceac8dbb90986bb96d14d320566d1c1a9991f7525c8f1b40614845b980ab' 
  AND token = 's6inAsvtywrH+DblYR5rp3Trr6h7QIS2IGS7XKquNXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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