SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'aac91754b335c091c7d7b376a0d1349f76b15df8a1061b1d706716274427fa8f' 
  AND token = 'iowykdxqCM3zzofBfOdMLfSvNdN4+IyPXRISiTpmFYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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