SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a4559dc60ef97e0aa0f3d06855e7162e44e930944337befd08385cf1f0c17fd' 
  AND token = 'iCrqOk+TktPpq/kuGsyiraG8b2zTxONnBIAxR5NhJGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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