SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a099035137067d31efa504a2d03ed20b2a0cecd571e4ce1fa052f103fcdde98a' 
  AND token = 'bNTAIhKQUUCvMw5u3D9YVkfZoeGCe+iZpMiWMmM7ooE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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