SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55688d8c0528bf8ffb4e18bff5571aa63c33fb6fb9024920e174c714a723a70c' 
  AND token = 'VGfawNGXAWqeeV3fG5LgxgYeQXDnH6pka76VTbXL+XE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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