SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd22c751541ac3a117267e0cf8401e393816fb4c5abfa9f06d7c9d8ac80f17d58' 
  AND token = 'PCp0qnpe+yFBAFzjuWVjOhqCXLZDsFA0OaLPsc28hhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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