SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f2233bc4ee878cb2b82fa6b8998589f483188aae68ab462e00e27d8364347e4' 
  AND token = '5nH91NpxXMOxSTb7osBDpfUHrEHycP/1JL0wkufSOnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}