SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81bf2890eb9b2a44bcf73ec9afec9b791d808aaff9c08ee00f064260992145ab' 
  AND token = '7+6wsigdYAojVpag4foGCzTP1HhfjtvghERfegFNUak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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