SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa73fc03175019a71be15006b59a900ea0b4466d6617fbc3a164e58f80816512' 
  AND token = 'SswFabC77sgQRe43n+AhRnkX85exr3PbLBdygHLH54U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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