SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '678db11c3dda3d944f6938233152572496ee6628ff167ea265df4011c1c3f42f' 
  AND token = 'BMp3rBsftvRaRbCuVu6b0BjFyY+NYfG/tuIVAl8VrYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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