SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90e095a23ea3b351c87095efc32eb2c789705e73d9d1afe594955d02f102a5be' 
  AND token = 'dlmLGMoxi78MOLknon8YGVSQ6Ks/36w8jNYVG66kMoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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